To integrate Google Sign-In functionality into your e-commerce website, you need to register and create a Google OAuth2 Project.
Steps to follow:
Access Google Cloud Console
Create a New Project (if you don’t have one yet)
Click Select a project > New Project.
Enter a project name, choose the location, and click Create.
After the project is created, click Select a project.
Select the newly created FcjFashionShop project.
Enable Google OAuth2 API
Under Quick access, select API & Services.
Or, in the left menu, select APIs & Services → Library.
Type Google+ API
in the search box and press Enter.
Click the Google+ API service.
Click Enable.
At this preparation step, you only need to create the Google OAuth2 Project and enable the necessary APIs. Creating the OAuth Consent Screen and configuring the Client ID/Client Secret will be done in later steps, after you have your actual domain/frontend URL.